Risk Evaluation of Potentially Toxic Metals in Soils and Vegetables Surrounding Lanzhou City in Gansu Province, China.

The potentially toxic metals in soil often cause secondary pollution of vegetables and pose a great threat to human health. Soil and vegetable samples were collected from eight different districts in the vegetable plantation base of Lanzhou city in Gansu province, and Zn, Cd, Cr, Cu, and Pb contents were determined using inductively coupled plasma atomic emission spectroscopy (ICP-AMS). The results suggested that the Cr and Zn contents of soils in the eight plantation bases were much higher than those of the other three metals. The metal contents showed significant differences among plantation bases and vegetable species, and the mean potentially toxic metal concentrations in soils exceeded background levels by 1.1~3.0 times. The accumulation of Cu in vegetables was significantly higher than that of other metals. Remarkable differences were found among the vegetables in the uptake abilities of Zn, Cd, Cr, and Cu. There were significant positive relationships between potentially toxic metal accumulation in vegetables and in soils. The results may be used to provide referential strategies and methods to minimize the impact of potentially toxic metals on human health through the consumption and cultivation of vegetables.